In feeding devices which are known from EP-B1-0 192 821 and EP-B1-0 192 851, the optoelectronic yarn sensing device determines the number of windings in the reserve or the position of the reserve limit at the withdrawal side to control the winding drive which winds yarn onto the storage drum which is designed as a rod cage (with stationary rods and advance rods) (reserve sensor or reference sensor). The light source arrangement, the receiver arrangement and the light guide which extends in a U-shaped bow are positioned in the same plane, which is vertical to the longitudinal axis of the storage drum, so that there is a spacing between inlet and outlet in the circumferential direction. A plurality of light source arrangements and receiver arrangements are lined up in the axial direction of the storage drum, and a plurality of light guides extending in the circumferential direction are arranged side by side in parallel in the storage drum. The circumferential distance prevents light which has been reflected by the light source arrangement in a scattered manner from passing to the receiver arrangement. Each light guide ensures that only light that has entered into the inlet is radiated from the outlet to the receiver arrangement. Inlet and outlet of each light guide are positioned in two separate advance rods of the storage drum. In the operative state of the winding drive, the advance rods carry out oscillating movements in relation to the light sources and receiver arrangements. The inlet and outlets at the advance members follow the oscillating movements. Moreover, the storage drum unavoidably oscillates about the axis of the storage drum during operation of the winding drive. The inlet and outlet of the same light guide are simultaneously covered by a yarn winding. The light source arrangement must be positioned in the same circumferential plane as the receiver arrangement. This makes a precise and reasonable evaluation of the signal difficult during the oscillatory and vibratory movement of the inlet and outlet. Moreover, the sensing device occupies a lot of space in the circumferential direction of the storage drum in an inappropriate manner.
It is the object of the present invention to provide a feeding device of the above-mentioned type in which significant signals that can easily be evaluated can be generated on the basis of the yarn sensing operation, with the advantage of light guides being maintained, and in which yarn can generally be sensed individually with movements that differ from one another.